High frequencies of both thalassemia trait (5.2%) and glucose 6-phosphate dehydrogenase (G6PD) deficiency for only males (1.3%) have been observed in the Calabrian population. The G6PD activity measurement was carried out on 1239 samples of whole blood from Calabrian subjects of both sexes (age range 10–55) by a differential pH-metry technique which was quite suitable to determine the G6PD deficiency in mass screenings. The analyzed subjects showed: only the thalassemia trait; or only the G6PD deficiency; or only the total iron serum deficiency; or G6PD deficiency associated with the thalassemia trait or with the total iron serum deficiency. The G6PD heterozygous subjects have an enzymatic activity which is masked by both the thalassemia trait and the total iron serum deficiency. In a population showing high frequencies of both thalassemia trait and G6PD deficiency, the comparison of G6PD activity of heterozygous subjects also affected with the thalassemia trait is more reliable if referred to the enzymatic activity of the carriers of the latter inherited anomaly rather than to G6PD activity of normal subjects.
